From: Dave Airlie <airlied@xxxxxxxxxx>
This patch has been added to the 3.18 stable tree. If you have any
objections, please let us know.
===============
[ Upstream commit 9eb1e57f564d4e6e10991402726cc83fe0b9172f ]
If we are doing an MST transaction and we've gotten HPD and we
lookup the device from the incoming msg, we should take the mgr
lock around it, so that mst_primary and mstb->ports are valid.
Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Dave Airlie <airlied@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
---
drivers/gpu/drm/drm_dp_mst_topology.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 34b1949..1f5e42a 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -1152,6 +1152,8 @@ static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_
struct drm_dp_mst_port *port;
int i;
/* find the port by iterating down */
+
+ mutex_lock(&mgr->lock);
mstb = mgr->mst_primary;
for (i = 0; i < lct - 1; i++) {
@@ -1171,6 +1173,7 @@ static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_
}
}
kref_get(&mstb->kref);
+ mutex_unlock(&mgr->lock);
return mstb;
}
--
2.1.0
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